Liquid crystal display device

ABSTRACT

A liquid crystal display device includes a first substrate, a second substrate facing the first substrate, a dual passivation layer disposed between the first substrate and the second substrate. The dual passivation layer includes a first passivation layer and a second passivation layer. A refractive index of the first passivation layer is different from a refractive index of the second passivation layer.

This application is a continuation of U.S. patent application Ser. No.12/899,019, filed on Oct. 6, 2010, which claims priority to KoreanPatent Application No. 10-2009-0127314, filed on Dec. 18, 2009, KoreanPatent Application No. 10-2009-0127315, filed on Dec. 18, 2009, andKorean Patent Application No. 10-2009-0127316, filed on Dec. 18, 2009,the contents of which in their entireties are herein incorporated byreference.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The general inventive concept relates to a liquid crystal displaydevice.

(2) Description of the Related Art

A liquid crystal display (“LCD”) device, which is a widely used type offlat panel display, typically displays an image by applying voltages toelectrodes disposed on substrates in the LCD to rearrange liquid crystalmolecules in a liquid crystal layer interposed between the electrodes,thereby controlling an amount of light transmitted through the liquidcrystal layer.

The LCD has an advantage of being thin, relative to other types ofdisplay devices, but side visibility is typically lower than frontvisibility in the LCD. Accordingly, various types of liquid crystalarrays and/or driving methods have been developed in attempts toincrease side visibility of the LCD. For example, in an attempt toimprove the viewing angle of an LCD, the LCD may include a substrate onwhich both a pixel electrode and a reference electrode are disposed.

However, when the LCD includes the substrate on which both the pixelelectrode and the reference electrode are disposed, parasiticcapacitance between the pixel and reference electrodes and a data lineis induced. However, when an interval between the pixel and referenceelectrodes and the data line is widened, to reduce the parasiticcapacitance therebetween, transmittance of the LCD is reduced.

Additionally, the transmittance is further reduced due to a reductionreaction of the pixel and reference electrodes during a manufacturingprocess of the pixel electrode and the reference electrode that uses atransparent material.

BRIEF SUMMARY OF THE INVENTION

In an exemplary embodiment, a liquid crystal display device includes afirst substrate, a second substrate facing the first substrate, a dualpassivation layer disposed between the first substrate and the secondsubstrate. The dual passivation layer includes a first passivation layerand a second passivation layer, where a refractive index of the firstpassivation layer is different from a refractive index of the secondpassivation layer.

In an exemplary embodiment, a liquid crystal display device includes afirst substrate, a second substrate facing the first substrate, a liquidcrystal layer interposed between the first substrate and the secondsubstrate, a gate line disposed between the first substrate and theliquid crystal layer, a data line disposed between the first substrateand the liquid crystal layer, a reference voltage line disposed betweenthe first substrate and the liquid crystal layer, a pixel connected tothe gate line and the data line. The pixel includes a thin filmtransistor connected to a first portion of the data line, a firstelectrode connected to the thin film transistor and including an openingformed therein overlapping the thin film transistor, and a secondelectrode disposed between the first electrode and the liquid crystallayer. The second electrode includes a first connection part disposedsubstantially parallel to the data line, a second connection partdisposed substantially parallel to the gate line and connected to thefirst connection part and a branch electrode which includes a firstpart, a second part connected to the first part; and a third partconnected to the first part and the second connection part. The secondpart forms a first angle with the first part, the third part forms asecond angle with the first part and a third angle with the secondconnection part, and a first opening is formed in the second electrodeoverlapping the thin film transistor and the first portion of the dataline.

In an exemplary embodiment, a liquid crystal display device includes afirst substrate, a second substrate facing the first substrate, a liquidcrystal layer interposed between the first substrate and the secondsubstrate, a data line disposed on the first substrate, and a pixeldisposed adjacent to the data line. The pixel includes a referenceelectrode disposed between the first substrate and the liquid crystallayer, and a pixel electrode disposed between the first substrate andthe reference electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects of the present invention will become morereadily apparent by describing in further detail exemplary embodimentsthereof with reference to the accompanying drawings, in which:

FIG. 1 is a plan view of an exemplary embodiment of a liquid crystaldisplay (“LCD”) device according to the present invention;

FIG. 2A is a partial cross-sectional view taken along line IIa-IIa ofFIG. 1;

FIG. 2B is a partial cross-sectional view taken along line IIb-IIb ofFIG. 1;

FIG. 3A is an enlarged view of portion A of FIG. 1;

FIG. 3B is an enlarged view of portion A′ of FIG. 1;

FIG. 3C is an enlarged view of portion A″ of FIG. 1;

FIG. 4 is a plan view of another exemplary embodiment of a liquidcrystal display device according to the present invention;

FIG. 5 is a plan view of still another exemplary embodiment of a liquidcrystal display device according to the present invention;

FIG. 6A is a plan view of yet another exemplary embodiment of a liquidcrystal display device according to the present invention;

FIG. 6B is a partial cross-sectional view taken along line VIB-VIB ofFIG. 6A;

FIG. 7A is a plan view of another exemplary embodiment of a liquidcrystal display device according to the present invention;

FIG. 7B is a partial cross-sectional view taken along line VIIB-VIIB ofFIG. 7A;

FIG. 8 is a plan view of still another exemplary embodiment of a liquidcrystal display device according to the present invention;

FIG. 9 is a partial cross-sectional view taken along line IX-IX of FIG.8;

FIG. 10 is a partial cross-sectional view taken along line X-X of FIG.8;

FIG. 11A is an enlarged view of portion A of FIG. 8;

FIG. 11B is an enlarged view of portion A′ of FIG. 8;

FIG. 12 is a plan view of yet another exemplary embodiment of a liquidcrystal display device according to the present invention;

FIG. 13 is a partial cross-sectional view taken along line XIII-XIII ofFIG. 12;

FIG. 14 is a plan view of another exemplary embodiment of a liquidcrystal display device according to the present invention;

FIG. 15 is a plan view of still another exemplary embodiment of a liquidcrystal display device according to the present invention;

FIG. 16 is a plan view of yet another exemplary embodiment of a liquidcrystal display device according to the present invention;

FIG. 17 is a partial cross-sectional view taken along line XVII-XVII ofFIG. 16;

FIG. 18 includes graphs of refractive index versus both flow rate ofnitrogen (N₂) gas and pressure of N₂ gas used in an exemplary embodimentof a chemical vapor deposition process according to the presentinvention;

FIG. 19 is a graph of transmittance versus thickness of an exemplaryembodiment of a passivation layer in a liquid crystal display deviceaccording to the present invention;

FIG. 20 is a graph of transmittance of an exemplary embodiment of aliquid crystal display device corresponding to refractive indexes of afirst and a second passivation layer thereof according to the presentinvention;

FIGS. 21A and 21B are microphotographs of a cross section of anexemplary embodiment of a transparent electrode according to the presentinvention;

FIG. 22 is a plan view of another exemplary embodiment of a liquidcrystal display device according to the present invention; and

FIG. 23 is a partial cross-sectional view taken along line XXIII-XXIIIof FIG. 22.

DETAILED DESCRIPTION OF THE INVENTION

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. This invention may, however, be embodied in many different forms,and should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like reference numerals refer tolike elements throughout.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the present invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises” and/or “comprising,” or“includes” and/or “including” when used in this specification, specifythe presence of stated features, regions, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, regions, integers, steps,operations, elements, components, and/or groups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

Hereinafter, exemplary embodiments of the present invention will bedescribed in further detail with reference to the accompanying drawings.

FIG. 1 is a plan view of an exemplary embodiment of a liquid crystaldisplay device according to the present invention, FIG. 2A is a partialcross-sectional view taken along line IIa-IIa of FIG. 1, and FIG. 2B isa partial cross-sectional view taken along line IIb-IIb of FIG. 1.

Referring to FIGS. 1 and 2, a liquid crystal display device according toan exemplary embodiment includes a lower display panel 100 and an upperdisplay panel 200 disposed opposite to, e.g., facing, the lower displaypanel 100, and a liquid crystal layer 3 interposed therebetween. Thelower display panel 100 will now be described in greater detail.

A gate conductor including a gate line 121 and a reference voltage line131 is disposed on an insulating substrate 110, which may be made oftransparent glass or plastic, for example. The gate line 121 includes agate electrode 124 and a wide end portion (not shown) which may beconnected to other layers or an external driving circuit (not shown),for example. The gate line 121 may be made of an aluminum-based metal,such as aluminum (Al) or an aluminum alloy, for example, a silver-basedmetal, such as silver (Ag) or a silver alloy, for example, acopper-based metal, such as copper (Cu) or a copper alloy, for example,a molybdenum (Mo) based metal, such as molybdenum (Mo) or a molybdenumalloy, for example, chromium (Cr), tantalum (Ta), titanium (Ti), andother metals. In an exemplary embodiment, the gate line 201 may have amultilayer structure including at least two conductive layers, which mayhave different physical properties.

The reference voltage line 131 transmits a constant reference voltageand, more specifically, includes an expanded portion 135 connected to areference electrode 270 and thereby transmits the reference voltage tothe reference electrode 270. The reference voltage line 131 may bedisposed substantially parallel to the gate line 121 along a firstdirection, e.g., a horizontal direction (as viewed in FIG. 1) and may bemade of the same material as the gate line 121, although additionalexemplary embodiments are not limited thereto.

A gate insulating layer 140, which may be made of silicon nitride (SiNx)or silicon oxide (SiOx), for example, is disposed on the gate lines 121and reference voltage line 131. The gate insulating layer 140 may have amultilayer structure including at least two insulating layers, which mayhave different physical properties.

A semiconductor island 154, which may be made of amorphous silicon(“a-Si”) or polysilicon (“p-Si”), for example, is disposed on the gateinsulating layer 140. At least a portion of the semiconductor island 154overlaps the gate electrode 124.

Ohmic contacts 163 and 165 are disposed on the semiconductor island 154.The ohmic contacts 163 and 165 may be made of materials such as n+hydrogenated amorphous silicon, for example, that is doped with n-typeimpurity such as phosphorous (P), for example, at high concentration, ormay be made of silicide. The ohmic contacts 163 and 165 may be disposedin pairs on a corresponding semiconductor island 154.

The data line 171 including the source electrode 173 and a dataconductor including a drain electrode 175 are disposed on the ohmiccontacts 163 and 165 and the gate insulating layer 140.

The data line 171 includes a wide end portion (not shown) connected toother layers or an external driving circuit (not shown), for example.The data line 171 transmits a data signal, and extends along a seconddirection, e.g., a vertical direction (as viewed in FIG. 1), which issubstantially perpendicular to the first direction, and therebyintersects with the gate line 121 and the reference voltage line 131. Inan exemplary embodiment, the data line 171 and the gate line 121 maydefine a pixel area, but additional exemplary embodiments are notlimited thereto.

In an exemplary embodiment, the data line 171 may include a first curvedpart including a chevron-like shape, e.g., a “V” shape, proximate to anintermediate, e.g., central, area of the pixel area to substantiallyimprove transmittance of the liquid crystal display device according toone or more exemplary embodiments. The data line 171 may further includea second curved part connected to the first curved part and forming apredetermined angle with the first curved part.

More specifically, for example, in an exemplary embodiment, the firstcurved part of the data line 171 may form an angle of about 7 angulardegrees (°) with a rubbing direction of an alignment layer. The secondcurved part, which is disposed in the intermediate area of the pixelarea, may extend from the first curved part to form an angle in a rangeof about 7° through about 15° with the first curved part.

The source electrode 173 is a portion of the data line 171 and isdisposed along the data line 171. The drain electrode 175 extends alonga direction substantially parallel to the source electrode 173. In anexemplary embodiment, the drain electrode 175 may be disposedsubstantially parallel to the data line 171, e.g., along the seconddirection.

The gate electrode 124, the source electrode 173 and the drain electrode175 form a thin film transistor (“TFT”) along with the semiconductorisland 154, and a channel of the thin film transistor is disposed on thesemiconductor island 154 between the source electrode 173 and the drainelectrode 175.

In an exemplary embodiment, the liquid crystal display device mayfurther include the source electrode 173 disposed on a same line onwhich the data line 171 is disposed and the drain electrode 175 disposedsubstantially parallel to the data line 171. Accordingly, a width of thethin film transistor may be increased without expanding a required spacefor the data conductor, and the aperture ratio of the liquid crystaldisplay device is thereby substantially increased.

In an exemplary embodiment, the data line 171 and the drain electrode175 may be made of a metal, such as molybdenum (Mb), chromium (Cr),tantalum (Ta), titanium (Ti), copper (Cu) or an alloy/alloys thereof,for example, and may have a multilayer structure including a refractorymetal layer (not shown) and a low resistance conductive layer (notshown). In an exemplary embodiment, the multilayer structure may have adouble layer including a lower layer of chromium, molybdenum or analloy/alloys thereof and an upper layer of aluminum or an alloy thereof,for example, a double layer including a lower layer of titanium or analloy thereof and an upper layer of copper or an alloy thereof, forexample, and a triple layer including a lower layer of molybdenum or analloy thereof, an intermediate layer of aluminum or an alloy thereof,and an upper layer of molybdenum or an alloy thereof, for example. Inadditional exemplary embodiments, the data line 171 and/or the drainelectrode 175 may be made of various metals or conductors including theabove-mentioned materials. The width of the data line 171 may be about3.5 micrometers (μm)±0.75 μm, but additional exemplary embodiments arenot limited thereto.

A pixel electrode 191 is disposed on a portion of the drain electrode175 and the gate insulating layer 140.

The pixel electrode 191 includes a pair of curved edges substantiallyparallel to a first curved part and a second curved part of the dataline 171.

The pixel electrode 191 is disposed on the drain electrode 175overlapping a portion of the drain electrode 175 and connected to thedrain electrode 175.

The pixel electrode 191 may be made of a transparent material such aspolycrystalline, single crystalline amorphous Indium tin oxide (“ITO”)or indium zinc oxide (“IZO”), for example.

A passivation layer 180 is disposed on the data line 171 and the drainelectrode 175, the exposed semiconductor island 154, and the pixelelectrode 191. The passivation layer 180 may be made of inorganicinsulator such as silicon nitride and silicon oxide, for example. Inanother exemplary embodiment, the passivation layer 180 may be made ofan organic insulator and the surface thereof may be planarized. Theorganic insulator may have photosensitivity, and the dielectric constantof the organic insulator may be about 4.0 or less. In an exemplaryembodiment, the passivation layer 180 may have a double-layer structure,including a lower inorganic layer and an upper organic layer, whichsubstantially improves insulating characteristic and effectivelyprotects the exposed part of the semiconductor island 154. The thicknessof the passivation layer 180 may be more than about 5000 angstroms (Å).In another exemplary embodiment, the thickness of the passivation layer180 may be in a range of about 6000 Å through about 8000 Å.

The passivation layer 180 may include a contact hole (not shown) thatexposes an end portion of the data line 171, and the passivation layer180 and the gate insulating layer 140 include a contact hole 183 thatexposes the expanded portion 135 of the reference voltage line 131 and acontact hole (not shown) that exposes the end part of the gate line 121.

The reference electrode 270 is disposed on the passivation layer 180.The reference electrode 270 overlaps the pixel electrode 191 andincludes a branch electrodes 271, a horizontal connection part 272connected to the branch electrodes 271, and a vertical connection part273 connected to the horizontal connection part 272. The referenceelectrode 270 may be made of transparent conductive materials such aspolycrystalline, single crystalline, amorphous ITO or IZO, for example.Reference electrodes 270 disposed in adjacent pixels are connected toeach other.

The branch electrode 271 of the reference electrode 270 includes a firstpart 271 a (shown in the dotted circle indicating portion A of FIG. 1)and a second part 271 b (shown in the dotted circle indicating portionA′ of FIG. 1) that are substantially parallel to the first curved partand second curved part of the data line 171, respectively. The firstpart 271 a forms an angle in a range of about 5° through about 10° withthe rubbing direction of the alignment layer. In an exemplaryembodiment, the first part 271 a forms an angle of about 7° with therubbing direction of the alignment layer. The second part 271 b mayextend from the first part 271 a forming an angle in a range of about 7°through about 15° with the first part 271 a.

The horizontal connection part 272 of the reference electrode 270 isdisposed substantially parallel to the gate line 121 and connected tothe branch electrodes 271. The horizontal connection part 272 of thereference electrode 270 disposed on the lower part of the pixel areaincludes the gate electrode 124 that forms the TFT, the semiconductorisland 154, the data line 171 that forms the source electrode 173, and afirst opening part 274, e.g., a first opening 274, that exposes thedrain electrode 175 and a portion of the reference voltage line 131. Thehorizontal connection part 272 of the reference electrode 270 has thereference electrode expanded portion 275 that extends along an expandedportion 135 of the reference voltage line 131. The reference electrodes270 disposed in adjacent pixels are connected to each other.

The branch electrode 271 of the reference electrode 270 further includesa third part 271 c (shown in the dotted circle indicating portion A″)connected to the horizontal connection part 272 of the referenceelectrode 270, where the third part 271 c may form an angle in a rangeof about 7° through about 15° with the first part 271 a. In an exemplaryembodiment, an angle (which may be an acute angle) between the firstpart 271 a of the branch electrode 271 of the reference electrode 270and the horizontal connection part 272 is greater than an angle (whichmay be an acute angle) between the second part 271 b and the horizontalconnection part 272 or an angle (which may be an acute angle) betweenthe third part 271 c and the horizontal connection part 272 by an anglein a range of about 7° through about 15°. The vertical connection part273 of the reference electrode 270 extends to overlap the data line 171disposed between two adjacent pixels and includes the first opening part274 disposed on a portion of the data line 171.

The first opening part 274 of the reference electrode 270 exposes thesource electrode 173 portion of the data line 171 and may have a widthin a range of about 30 μm through about 60 μm.

The expanded portion 275 of the reference electrode 270 is connected tothe reference voltage line 131 through the contact hole 183 formed inthe passivation layer 180 and the gate insulating layer 140.

In an exemplary embodiment, the alignment layer (not shown) may bedisposed on the reference electrode 270 and the passivation layer 180,and the alignment layer may be a horizontal alignment layer and rubbedin a predetermined direction. More specifically, for example, therubbing direction of the alignment layer may form an angle in a range ofabout 5° through 10° with the first part 271 a of the branch electrodeof the reference electrode 270. In another exemplary embodiment, therubbing direction of the alignment layer may form an angle of about 7°with the first part 271 a.

The upper display panel 200 will now be described in greater detail.

Still referring to FIGS. 1 and 2, a light blocking member 220 isdisposed on an insulating substrate 210, which may be made oftransparent glass or plastic, for example. The light blocking member 220is also referred to as a black matrix 220, and prevents light leakage.

Color filters 230 are disposed on the insulating substrate 210. In anexemplary embodiment, the color filters 230 may be disposed in an areasurrounded by the light blocking member 220 and may extend in a verticaldirection along a column of a pixel electrode 191. Each color filter 230may display one primary color of primary colors (e.g., red, green andblue).

An overcoat 250 is disposed on the color filters 230 and the lightblocking member 220. The overcoat 250 may be made of an insulatingmaterial, e.g., an organic insulating material, and effectively preventsthe color filters 230 from being exposed, and also provides a planarizedplane. In one or more exemplary embodiments, the overcoat 250 may beomitted.

The liquid crystal layer 3 includes a nematic liquid crystal materialhaving positive dielectric anisotropy. Liquid crystal molecules 31 ofthe liquid crystal layer 3 are aligned such that longitudinal axes ofthe liquid crystal molecules 31 are arranged substantially parallel to aplane defined by parallel facing surfaces of the lower display panel 100and the upper display panel 200, and a direction of the longitudinalaxes of the liquid crystal molecules 31 is spirally twisted about 90°with respect to the rubbing direction of the alignment layer from thelower display panel 100 to the upper display panel 200.

The pixel electrode 191 receives a data voltage from the drain electrode175, and the reference electrode 270 receives a common voltage from thereference voltage line 131. The reference electrode 270 is connected toanother reference electrode that receives the reference voltage, but thereference electrode 270 receives the reference voltage from a referencevoltage applying unit (not shown) disposed outside of a display areathrough the reference voltage line 131 to prevent a voltage drop in thedisplay area.

The pixel electrode 191 that receives the data voltage and the referenceelectrode 270 that receives the common voltage generate an electricfield, and the liquid crystal molecule 31 of the liquid crystal layer 3disposed between the pixel electrode 191 and the reference electrode 270thereby rotates in a direction substantially parallel to the directionof the electric field. As described above, polarization of lighttransmitted through the liquid crystal layer is determined according tothe rotated direction of the liquid crystal molecules 31.

Thus, the liquid crystal molecules 31 of the liquid crystal layer 3 ofthe liquid crystal display device rotate according to the electric fieldformed between the edge of the branch electrode 271 of the referenceelectrode 270 and the pixel electrode 191. In an exemplary embodiment,since the alignment layer is rubbed such that the liquid crystalmolecules 31 of the liquid crystal layer 3 are aligned with a pre-tiltangle and the rubbing angle may be in a range of about 5° through about10° (e.g., about 7°) with the branch electrode 271 of the referenceelectrode 270, the liquid crystal molecules 31 rotate rapidly in apre-tilted direction.

The pixel electrode 191 of the liquid crystal display device is disposedbetween the gate insulating layer 140 and the passivation layer 180 andconnected to the drain electrode 175 by covering a portion of the drainelectrode 175, and the aperture ratio is thereby substantiallyincreased.

In an exemplary embodiment, the liquid crystal display device includes asource electrode 173 disposed along a portion of the data line 171 and adrain electrode 175 extending substantially parallel to a portion of thedata line 171. Accordingly, the width of the thin film transistor issubstantially increased without requiring the widening of an area inwhich the data conductor is disposed, and the aperture ratio of theliquid crystal display device is thereby further increased.

In an exemplary embodiment, the reference electrode 270 disposed on thepassivation layer 180 includes a gate electrode 124 of the TFT, thesemiconductor island 154, and an opening part 74 that exposes a portionof the data line 171, e.g., the source electrode 173, and the drainelectrode 175. Accordingly, the parasitic capacitance between the dataline 171 and the reference electrode 270 is thereby substantiallyreduced.

Hereinafter, experimental results showing the parasitic capacitancereduction between the data line 171 and the reference electrode 270 willbe described in further detail. Table 1 shows a ratio of measured valuesof the parasitic capacitance between the data line 171 and the referenceelectrode 270 for experimental groups of the liquid crystal displaydevice relative to a control group, which is a conventional liquidcrystal display device, as a percentage. Specifically, the parasiticcapacitance between the data line 171 and the reference electrode 270was measured from liquid crystal display devices including differentshapes of the data line 171 and the drain electrode 175 that forms thethin film transistor of liquid crystal display device, different openingparts of the reference electrode 270, different line widths of the dataline 171 and different thicknesses of the passivation layer 180.

TABLE 1 A 71.0% B 62.1% C 49.6%

In Table 1, the parasitic capacitance between the reference electrode270 and the data line 171 of the liquid crystal display device in theexperimental groups are expressed as a percentage with respect to aparasitic capacitance between a reference electrode and a data line of aconventional liquid crystal display device including U-shaped drainelectrode and an organic insulating layer disposed between the referenceelectrode and the data line. Group A includes liquid crystal displaydevice having the source electrode 173 that is a portion of the dataline 171 and disposed along the data line 171 and the drain electrode175 extending substantially parallel to the data line 171, where thereference electrode 270 includes the gate electrode 124 that forms thethin film transistor, the semiconductor island 154, and the firstopening part 274 that exposes the source electrode 173 that is a portionof the data line 171, the drain electrode 175, and a portion of thereference voltage line 131. Group B includes a liquid crystal displaydevice, the same as the liquid crystal display device of Group A exceptfor the line width of the data line formed at about 3.5 μm, and Group Cincludes a liquid crystal display device, the same as the liquid crystaldisplay device of group B except for the thickness of the passivationlayer 180 formed at about 8000 Å.

As shown in Table 1, the parasitic capacitance between the referenceelectrode 270 and the data line 171 of Group A is reduced to about 71.0%as compared to the conventional liquid crystal display device, theparasitic capacitance between the reference electrode 270 and the dataline 171 of Group B is reduced to about 62.1% by controlling the linewidth of the data line 171 and the parasitic capacitance between thereference electrode 270 and the data line 171 of Group C is reduced toabout 49.6% by controlling the thickness of the passivation layer 180.

As described above, an exemplary embodiment of a liquid crystal displaydevice according to the present invention has substantially improvedaperture ratio, substantially reduced parasitic capacitance between thedata line 171 and the reference electrode 270, without a complicatedmanufacturing process, and, accordingly, a substantially reduced and/oreffectively prevented deterioration of image quality due to theparasitic capacitance.

The shape of the branch electrode 271 of the reference electrode 270according to an exemplary embodiment of the liquid crystal displaydevice will now be described in further detail with reference to FIGS.3A through 3C. FIG. 3A is an enlarged view of portion A of FIG. 1, whichis the first part 271 a of the reference electrode 270, FIG. 3B is anenlarged view of portion A′ of FIG. 1, which is the second part 271 b ofthe reference electrode 270, and FIG. 3C is an enlarged view of portionA″ of FIG. 1, which is the third part 271 c of the reference electrode270.

Referring to FIG. 3A, the first part 271 a of the branch electrode 271of the reference electrode 270 is disposed in a direction forming afirst angle θ1 with the rubbing direction of the alignment layerdisposed on the lower display panel 100. As described above, the firstangle θ1 may be in a range of about 5° through about 10° (e.g., about7°). Referring to FIG. 3B, the second part 271 b of the branch electrode271 of the reference electrode 270 is disposed in a direction forming asecond angle θ2 with the first part 271 a, and referring to FIG. 3C, thethird part 271 c of the reference electrode 270 is disposed in adirection forming the second angle θ2 with the first part 271 a. In anexemplary embodiment, the second angle θ2 may be in a range of about 7°through about 15°.

As described above, the branch electrode 271 of the reference electrode270 includes the first part 271 a, the second part 271 b and the thirdpart 271 c, and the direction of the electric filed generated at thecentral part and edge part of the pixel area is thereby changed. In aconventional liquid crystal display device, however, the direction ofthe electric field at the edge part of the branch electrode 271 issubstantially different from the direction of the electric field at thecentral part of the branch electrode 271, and the aligned directions ofthe liquid crystal molecules are largely irregular when the electricfield is generated in the liquid crystal layer 3, and an undesiredtexture is thereby generated in the image. In an exemplary embodiment,however, the liquid crystal display device includes the second part 271b and the third part 271 c that form an angle with the rubbing directiongreater than an angle that the first part 271 a forms with the rubbingdirection to adjust the direction of the electric field at the edge partand the central part of the branch electrode 271, and the liquid crystalmolecules of the liquid crystal layer 3 are thereby aligned in apredetermined direction by rotating in predetermined directions.Accordingly, any texture due to irregular rotation of the liquid crystalmolecule 31 at the central part or the upper and lower boundary part ofthe pixel area is effectively prevented.

In an exemplary embodiment, the branch electrode 271 of the referenceelectrode 270 includes the first part 271 a, the second part 271 b andthe third part 271 c for the liquid crystal molecules 31 to rotate indifferent directions when the electric field is generated by the branchelectrodes 271, and the viewing angle of the liquid crystal displaydevice is thereby substantially increased and the color tone iseffectively compensated.

Another exemplary embodiment will now be described in further detailwith reference to FIG. 4, which is a plan view of a liquid crystaldisplay device according to the present invention.

The structure of the liquid crystal display device of FIG. 4 issubstantially the same as the structure of the exemplary embodiments ofthe liquid crystal display device shown in FIGS. 1 and 2 and describedin greater detail above. The same or like elements shown in FIG. 4 havebeen labeled with the same reference characters as used in FIGS. 1 and2, and any repetitive detailed description thereof will hereinafter beomitted or simplified.

As shown in FIG. 4, the liquid crystal display device includes at leastthree adjacent pixels, where a pixel of the at least three adjacentpixels includes a spacer 325. The spacer 325 may be disposed on theexpanded portion 135 of the reference voltage line 131 and an area ofthe spacer 325 is greater than an area of the contact hole 183 thatconnects the reference voltage line 131 and the reference electrode 270.

In an exemplary embodiment, the pixel including the spacer 325 (of theat least three adjacent pixels) does not include the contact hole 183that connects the reference voltage line 131 and the reference electrode270, while the other pixels (of the at least three adjacent pixels)includes the contact hole 183. Therefore, the reference voltage line 131and the reference electrode 270 may be connected through the contacthole 183 in a pixel area in which the spacer 325 is not disposed. Whenthe spacer 325 is disposed on the contact hole 183, a pixel distance maybe inaccurate due to a step difference caused by the contact hole 183.In an exemplary embodiment, the accuracy of the pixel distance isincreased by disposing the spacer 325 only in a pixel where the contacthole 183 that connects the reference voltage line 131 and the referenceelectrode 270 is not formed.

A part of the light blocking member 220 corresponding to the spacer 325disposed in the pixel including the spacer 325 among the three adjacentpixels is expended, and thereby covers the spacer 325. Therefore, theaperture ratio of the pixel in which the spacer 325 is disposed may beless than the aperture ratios of the other pixels.

The at least three adjacent pixels may display different colors, and thepixel including the spacer 325 has the smallest aperture ratio among theat least three adjacent pixels, and may be a green pixel. In anexemplary embodiment, yellow discoloration of the liquid display deviceis effectively prevented where the aperture ratio of a green pixel issmaller than the aperture ratios of other color pixels.

Another exemplary embodiment of the liquid crystal display device willnow be described in further detail with reference to FIG. 5. FIG. 5 is aplan view of a liquid crystal display device according to the presentinvention.

The structure of the liquid crystal display device of FIG. 5 issubstantially the same as the structure the liquid crystal displaydevice in FIGS. 1 and 2 except for the reference voltage line 131. Thesame or like elements shown in FIG. 5 have been labeled with the samereference characters as used above to describe the exemplary embodimentsof the liquid crystal display device shown in FIGS. 1 and 2, and anyrepetitive detailed description thereof will hereinafter be omitted orsimplified.

As described above, and in the exemplary embodiment of the liquidcrystal display device shown in FIG. 5, the reference voltage line 131is disposed at the central part of the pixel area, and the expandedportion 135 of the reference voltage line 131 is disposed in the centralpart of the pixel area and the expanded portion 275 of the referenceelectrode 270 is disposed in the central part of the pixel area.

The contact hole 183 that connects the reference voltage line 131 andthe reference electrode 270, the expanded portion 135 of the referencevoltage line 131, and the expanded portion 275 of the referenceelectrode 270 may be disposed in one pixel of three adjacent pixels, andthe contact hole 183 may not be formed in other pixels of the threeadjacent pixels. Therefore, the reference voltage line 131 and thereference electrode 270 can be connected through the contact hole 183 inthe one pixel of the three neighboring pixels. A contact area of thereference voltage line 131 and the reference electrode 270 may bedisposed adjacent to the data line 171.

In the one pixel where the reference voltage line 131 and the referenceelectrode 270 are connected to each other through the contact hole 183of the three adjacent pixels, an edge of the pixel electrode 191adjacent to the data line 171 may include a cutout 192 formed in aportion corresponding to the expanded portion 135 of the referencevoltage line 131, the contact hole 183 and the expanded portion 275 ofthe reference electrode 270 and surrounding at least a portion of thecontact area of the reference voltage line 131 and the referenceelectrode 270. Accordingly, the pixel electrode 191 disposed between thereference voltage line 131 and the reference electrode 270 is notoverlapping the contact part of the reference voltage line 131 and thereference electrode 270, and a short between the reference electrode 270and the pixel electrode 191 is thereby effectively prevented.

In an exemplary embodiment, when the contact hole 183 that connects thereference voltage line 131 and the reference electrode 270, the expandedportion 135 of the reference voltage line 131 and the expanded portion275 of the reference electrode 270 are disposed in the one pixel of thethree adjacent pixels, the aperture ratio of the one pixel where thereference voltage line 131 and the reference electrode 270 are connectedmay be less than the aperture ratios of the other pixels of the threeadjacent pixels.

The three adjacent pixels may display different colors, and the onepixel where the reference voltage line 131 and the reference electrode270 are connected and that has the less aperture ratio may be a greenpixel.

As described above, by connecting the reference voltage line 131 and thereference electrode 270 only in a part of the pixels, the apertureratios of the other pixels of the pixels can be increased, and theentire aperture ratio of the liquid crystal display device is therebysubstantially increased. In an exemplary embodiment, the aperture ratioof the green pixel may be less than the aperture ratios of the otherpixels displaying other colors, and yellow discoloration of the liquidcrystal display device is thereby effectively prevented.

Another exemplary embodiment of the liquid crystal display device nowwill be described in further detail with reference to FIGS. 6A and 6B.FIG. 6A is a plan view of yet another exemplary embodiment of a liquidcrystal display device according to the present invention, and FIG. 6Bis a partial cross-sectional view taken along line VIB-VIB of FIG. 6A.

The structure of the exemplary embodiment of the liquid crystal displaydevice of FIGS. 6A and 6B is substantially the same as the structure theliquid crystal display in FIGS. 1 and 2 except that the liquid crystaldisplay device of FIGS. 6A and 6B further includes a shielding electrode88 and a second opening part 276, e.g., a second opening 276. The sameor like elements shown in FIGS. 6A and 6B have been labeled with thesame reference characters as used above to describe the exemplaryembodiments of the liquid crystal display device shown in FIGS. 1 and 2,and any repetitive detailed description thereof will hereinafter beomitted or simplified.

As described above, the liquid crystal display device shown in FIGS. 6Aand 6B includes the shielding electrode 88 disposed below the data line171 and the second opening part 276 disposed above the data line 171 andformed in the vertical connection part 273 overlapping the data line171. The shielding electrode 88 may be disposed in a same layer on whichthe gate conductor is disposed and may be floated. The shieldingelectrode 88 effectively prevents light leakage. The vertical length ofthe second opening part 276 of the reference electrode 270 disposedabove the data line 171 may be greater than half of the vertical lengthof the data line 171 disposed in one pixel. As described above, aportion of the vertical connection part 273 of the reference electrode270 disposed on the data line 171 is not overlapping the data line 171by having the second opening part 276 formed therein, and the parasiticcapacitance between the data line 171 and the reference electrode 270 isthereby substantially reduced.

Referring to FIG. 6B, a width d1 of the shielding electrode 88 may be ina range of about 8.2 μm through about 8.8 μm, and a distance d2 betweenthe shielding electrode 88 and the pixel electrode 191 may be in a rangeof about 4.7 μm through about 5.3 μm. A width d3 of the data line 171may be in a range of about 3.2 μm through about 3.8 μm, and a width d4of the second opening 276 of the reference electrode 270 disposed on thedata line 171 may be in a range of about 4.2 μm through about 4.8 μm. Inan exemplary embodiment, the width d4 of the second opening 276 of thereference electrode 270 disposed on the data line 171 is greater thanthe width d3 of the data line 171, the data line 171 and the referenceelectrode 270 are not overlapping each other by the second opening 276,and the parasitic capacitance due to the overlap of the data line 171and the reference electrode 270 is substantially reduced. In anexemplary embodiment, a width d5 of the branch electrode 271 of thereference electrode 270 may be in a range of about 4.2 μm through about4.8 μm, the branch electrode 271 adjacent to the data line 171 and theshielding electrode 88 may overlap each other, and a width d6 of theoverlapped part may be in a range of about 1.7 μm through about 2.3 μm.

Another embodiment of the liquid crystal display device now will bedescribed in further detail with reference to FIGS. 7A and 7B. FIG. 7Ais a plan view of another exemplary embodiment of a liquid crystaldisplay device according to the present invention, and FIG. 7B is apartial cross-sectional view taken along line VIIB-VIIB of FIG. 7A.

The structure of the liquid crystal display device of FIGS. 7A and 7B issubstantially similar to the structure the liquid crystal display devicein FIGS. 1 and 2 except for the reference electrode 270. The same orlike elements shown in FIGS. 7A and 7B have been labeled with the samereference characters as used above to describe the exemplary embodimentsof the liquid crystal display device shown in FIGS. 1 and 2, and anyrepetitive detailed description thereof will hereinafter be omitted orsimplified.

The gate line 121, which includes the gate electrode 124, and thereference voltage line 131 are disposed on the insulating substrate 110,and the gate insulating layer 140 is disposed on the gate line 121 andthe reference voltage line 131. The semiconductor island 154, the ohmiccontacts 163 and 165 are disposed on the gate insulating layer 140, andthe data line 171 and the drain electrode 175, which include the sourceelectrode 173, are disposed on the gate insulating layer 140 and theohmic contacts 163 and 165. The pixel electrode 191 is disposed on thegate insulating layer 140 and a portion of the drain electrode 175, andthe passivation layer 180 having the contact hole 183 is disposed on thepixel electrode 191, the data line 171, the drain electrode 175 and theexposed semiconductor island 154. The reference electrode 270 includingthe branch electrode 271 is disposed on the passivation layer 180,overlapping the pixel electrode 191.

As shown in FIG. 7A, the reference electrode 270 of the liquid crystaldisplay device overlaps the pixel electrode 191, and includes aplurality of branch electrodes 271, a horizontal connection part 272(hereinafter, the horizontal connection part will be referred to as the“first connection part”) connected to the plurality of branch electrodes271 and a vertical connection part 273 (hereinafter, the verticalconnection part 273 will be referred to as the “second connection part”)connected to the first connection part 272 and a reference electrode 270disposed in an adjacent pixel.

The branch electrode 271 of the reference electrode 270 extendssubstantially parallel to the gate line 121. In another exemplaryembodiment the branch electrode 271 may be disposed in a directionforming an angle in a range of about 5° through about 20° with the gateline 121. In an exemplary embodiment, the branch electrode 271 of thereference electrode 270 may be disposed in a direction forming an anglein a range of about 7° through about 13° (e.g., about 10°) with therubbing direction of the alignment layer.

The branch electrode 271 of the reference electrode 270 includes a firstpart 271 a extending from the branch electrode 271 and a second part 271b extending from an end of the first part 271 a.

In an exemplary embodiment, the first part 271 a of the branch electrode271 of the reference electrode 270 forms an angle of about 10° with therubbing direction of the arrangement layer, and the second part 271 bmay be disposed in a direction forming an angle in a range of about 7°through about 15° with the first part 271 a.

Another embodiment of the liquid crystal display device now will bedescribed in further detail with reference to FIGS. 8 through 10. FIG. 8is a plan view of another exemplary embodiment of a liquid crystaldisplay device according to the present invention, FIG. 9 is a partialcross-sectional view taken along line IX-IX of FIG. 8 and FIG. 10 is apartial cross-sectional view taken along line X-X of FIG. 8.

Referring to FIGS. 8 through 10, the liquid crystal display deviceincludes the lower display panel 100, the upper display panel 200disposed opposite to the lower display panel 100 and the liquid crystallayer 3 interposed therebetween.

The lower display panel 100 will now be described in further detail.

The gate line 121 and the gate conductor including the reference voltageline 131 are disposed on the insulating substrate 110, which may be madeof a transparent glass or plastic, for example. The gate line 121includes the gate electrode 124 and a wide end portion (not shown),which may be connected to other layers or external driving circuits, forexample. The reference voltage line 131 transmits a predeterminedreference voltage and includes the expanded portion 135 connected to thereference electrode 270. The reference voltage line 131 is connected tothe reference electrode 270 and transmits the common voltage to thereference electrode 270. The reference voltage line 131 may be disposedsubstantially parallel to the gate line 121 and may be made of amaterial same as the material of which the gate line 121 may be made of.

The gate insulating layer 140 may be made SiNx or SiOx, for example, andis disposed on the gate conductors, e.g., the gate line 121 and thereference voltage line 131. The gate insulating layer 140 may have themultilayer structure including at least two insulating layers ofdifferent physical properties.

Semiconductor stripes 151, which may be made of hydrogenated a-Si p-Si,for example, are disposed on the gate insulating layer 140. Thesemiconductor stripe 151 extends in a direction substantially parallelto the data line 171 and includes a plurality of projection parts 154extending toward the gate electrode 124.

Stripe ohmic contacts 161 and island ohmic contacts 165 are disposed onthe semiconductor stripe 151. The ohmic contacts 161 and 165 may be madeof materials such as n+ hydrogenated a-Si doped with an n-type impurity,e.g., phosphorous (P), at high concentration or may be made of silicide.The ohmic contacts 161 include a projection part 163, and the projectionpart 163 and the ohmic contacts 165 are disposed in pairs on theprojection part 154 of the semiconductor stripe 151.

The data line 171 and the drain electrode 175 are disposed on the ohmiccontacts, e.g., stripe ohmic contacts 161 and island ohmic contacts 165,and the gate insulating layer 140.

The data line 171 transmits the data signal and extends in a directionsubstantially vertical to the gate line 121 and the reference voltageline 131, and thereby intersects the gate line 121 and the referencevoltage line 131.

The data line 171 includes the source electrode 173 extending to thegate electrode 124 and a wide end portion (not shown), which may beconnected to other layers or the external driving circuits.

In an exemplary embodiment, the data line 171 may include an extendedportion disposed adjacent to the gate line 121 and the reference voltageline 131 to prevent short-circuit.

The drain electrode 175 is disposed at a distance from the data line 171and opposite to the source electrode 173, and the gate electrode 124 isdisposed adjacent to the drain electrode 175 and the data line 171.

The drain electrode 175 includes a narrow part and an expanded part. Aportion of the narrow part is surrounded by the source electrode 173.

The gate electrode 124, the source electrode 173 and the drain electrode175 forms TFT along with the projection part 154 of the semiconductorstripe 151, and a channel of the thin film transistor is formed on thesemiconductor island 154 between the source electrode 173 and the drainelectrode 175.

The pixel electrode 191 is disposed on the expanded part of the drainelectrode 175 and the gate insulating layer 140.

The pixel electrode 191 has an edge substantially parallel to the dataline 171 or the gate line 121 and has a substantially rectangular (whichmay be a square) shape.

The pixel electrode 191 overlaps the expanded part of the drainelectrode 175, and is thereby connected to the drain electrode 175disposed thereon.

The pixel electrode 191 may be made of transparent materials such aspolycrystalline, single crystalline amorphous ITO or IZO, for example.

The passivation layer 180 is disposed on the data conductors, e.g., thedata line 171 and the drain electrode 175, the exposed semiconductorisland 154 and the pixel electrode 191. The passivation layer 180 ismade of an inorganic insulator such as silicon nitride or silicon oxide,for example. In an exemplary embodiment, the passivation layer 180 maybe made of an organic insulator, and the surface of the passivationlayer 180 may be planarized. The organic insulator may havephotosensitivity and the dielectric constant of the organic insulatormay be less than about 4.0. In an exemplary embodiment, the passivationlayer 180 may have a double-layer structure, including a lower inorganiclayer and an upper organic layer, which has substantially improvedinsulating characteristic of the organic layer effectively protect theexposed part of the semiconductor island 154.

The passivation layer 180 includes a contact hole (not shown) formedtherein that exposes an end portion of the data line 171, and thepassivation layer 180 and the gate insulating layer 140 include acontact hole 183 that exposes the expanded portion 135 of the referencevoltage line 131, and a contact hole (not shown) that exposes an endportion of the gate line 121.

The reference electrode 270 is disposed on the passivation layer 180.The reference electrode 270 overlaps the pixel electrode 191 andincludes the first connection part 272 connected to the plurality ofbranch electrodes 271, the second connection part 273 and referenceelectrodes 270 of adjacent pixels. The reference electrode 270 may bemade of transparent conductive materials, such as polycrystalline,single crystalline, amorphous ITO or IZO, for example.

The branch electrode 271 s of the reference electrode 270 may bedisposed in a direction forming an angle in a range of about 5° throughabout 20° with the gate line 121. In an exemplary embodiment, the branchelectrode 271 of the reference electrode 270 may be disposed in adirection forming an angle of about 10° with the rubbing direction ofthe alignment layer.

The branch electrode 271 of the reference electrode 270 includes thefirst part 271 a (shown in the dotted circle indicating portion A ofFIG. 8) extending in a predetermined direction and the second part 271 b(shown in the dotted circle indicating portion A′ of FIG. 8) extendingfrom of the first part 271 a disposed adjacent to the first connectionpart 272.

The first part 271 a of the branch electrode 271 of the referenceelectrode 270 forms an angle in a range of about 7° through about 13°,e.g., about 10°, with the rubbing direction of the alignment layer andthe second part 271 b may be disposed in a direction forming an angle ina range of about 7° through about 15° with the first part 271 a.

The first part 271 a and the second part 271 b of the branch electrodes271 will now be described in greater detail with reference to FIGS. 11Aand 11B. FIG. 11A is an enlarged view of portion A of FIG. 8, which isthe first part 271 a of the reference electrode, and FIG. 11B is anenlarged view of portion A′ of FIG. 8, which is the second part 271 b ofthe reference electrode.

Referring now to FIGS. 11A and 11B, the first part 271 a of the branchelectrode 271 of the reference electrode 270 is disposed in a directionforming a first angle θ1 with the rubbing direction of the alignmentlayer disposed on the lower display panel 100. As described above, thefirst angle θ1 may be in a range of about 7° through about 13°, e.g.,about 10°. In addition, the second part 271 b of the branch electrode271 of the reference electrode 270 extends from the first part 271 aforming a second angle θ2 with the first part 271 a. The second angle θ2may be in a range of about 7° through about 15°

As described above, the branch electrode 271 of the reference electrode270 includes the first part 271 a and the second part 271 b, and thedirections of the electric filed generated at the central part and atedge part of the pixel area are thereby changed. In a conventionalliquid crystal display device, the diction of the electric filed at theedge part of the branch electrode 271 is different from the direction ofthe electric field at the central part of the branch electrode 271, andwhen the electric field is generated in the liquid crystal layer 3, thealigned directions of the liquid crystal molecules are irregular, and atexture is thereby generated. In an exemplary embodiment, however, thereference electrode includes the second part 271 b extending from an endportion of the first part 271 a forming an angle with the first part 271a to change the directions of the electric field generated in the liquidcrystal layer 3, and the liquid crystal molecules in the liquid crystallayer 3 are thereby rotated in a predetermined direction and therotation direction of the liquid crystal molecules is thereby determinedwhen the liquid crystal molecule 31 rotates. Accordingly, texture due toany irregular rotation of the liquid crystal molecule 31 at the left andright boundary area of the pixel area is thereby effectively prevented.In an exemplary embodiment, the branch electrode 271 of the referenceelectrode 270 includes the first part 271 a and the second part 271 b todifferently set the rotation angle of the liquid crystal molecule 31,and the viewing angle of the liquid crystal display device is therebysubstantially increased and the color tone is effectively compensated.

Referring again to FIGS. 8 and 10, the reference electrodes 270 disposedin pixels disposed adjacent to each other are connected to each other bythe second connection part 273, and the second connection part 273overlaps a portion of the data line 171. The length of the portion ofthe data line 171 that overlaps the second connection part 273 issubstantially less than the entire length of the data line 171 disposedin one pixel area.

The reference electrode 270 is connected to the reference voltage line131 through the contact hole 183 formed on the passivation layer 180 andthe gate insulating layer 140.

In an exemplary embodiment, the alignment layer (not shown) is disposedon the reference electrode 270 and the passivation layer 180, and thealignment layer may be a horizontal alignment layer and rubbed in apredetermined direction. The rubbing direction of the alignment layermay form an angle of about 10° with a direction in which the first part271 a of the branch electrode of the reference electrode 270 extends.

The upper display panel 200 now will now be described in further detail.

The light blocking member 220 is disposed on the insulating substrate210, which may be made of transparent glass or plastic, for example. Thelight blocking member 220, also referred to as a black matrix, preventslight leakage.

Color filters 230 are disposed on the insulating substrate 210. Thecolor filters 230 may be disposed overlapping an area surrounded by thelight blocking member 220 and extending along a substantially verticaldirection along a column of the pixel electrode 191. Each of the colorfilters 230 may display one primary color of three primary colors (e.g.,one of red, green and blue).

The overcoat 250 is disposed on the color filters 230 and the lightblocking member 220. The overcoat 250 may be made of an insulatingmaterial, e.g., an organic insulating material, and prevents exposure ofthe color filters 230 and provides the planarized plane. In one or moreexemplary embodiments, the overcoat 250 may be omitted.

The liquid crystal layer 3 includes a nematic liquid crystal materialhaving positive dielectric anisotropy. The liquid crystal molecules ofthe liquid crystal layer 3 have a structure in which the direction ofthe longitudinal axis is arranged parallel to a plane defined byparallel surfaces of the lower display panel 100 and the upper displaypanel 200 and twisted spirally by 90° from the rubbing direction of thealignment layer of the lower display panel 100 to the upper displaypanel 200.

The pixel electrode 191 receives a data voltage from the drain electrode175, and the reference electrode 270 receives a predetermined referencevoltage from the reference voltage line 131.

The pixel electrode 191 that receives the data voltage and the referencevoltage line 131 that receives the common voltage generate an electricfield, and the liquid crystal molecules of the liquid crystal layer 3disposed above the pixel electrode 191 and the reference electrode 270rotate in a direction parallel to the direction of the electric field.As described above, polarization of light that transmits the liquidcrystal layer is changed according to the rotation direction of theliquid crystal molecules when the electric filed is generated therein.

As described above, the liquid crystal molecules 31 of the liquidcrystal layer 3 of the liquid crystal display device rotatecorresponding to an electric field generated between the edge of thebranch electrode 271 of the reference electrode 270 and the pixelelectrode 191. In an exemplary embodiment, since the alignment layer isrubbed such that the liquid crystal molecule 31 is pre-titled at apredetermined angle and the rubbing angle forms about 7° with the branchelectrode 271 of the reference electrode 270, the liquid crystalmolecule 31 is thereby rotated rapidly in a pre-tilted direction.

In an exemplary embodiment, the pixel electrode 191 of the liquidcrystal display device is disposed between the gate insulating layer 140and the passivation layer 180 and overlaps a portion of the drainelectrode 175 to be connected to the drain electrode 175. Accordingly,the aperture ratio may be greater than the aperture ratio of aconventional liquid crystal display device in which a pixel electrodeand a drain electrode are connected through a contact hole.

In an exemplary embodiment, the first connection part 272 connected tothe branch electrodes 271 of the reference electrode 270 is disposedparallel to the data line 171, and the aperture ratio of the liquidcrystal display device is thereby increased while the parasiticcapacitance between the pixel electrode 191 and the data line 171 issubstantially reduced.

Relationships between the data line 171, the reference electrode 270 andthe pixel electrode 191 according to one or more exemplary embodimentswill now be described in greater detail with reference to FIG. 10.

As shown in FIG. 10, the liquid crystal display device includes thepixel electrode 191 and the data line 171 disposed on the gateinsulating layer 140 with a first interval therebetween, the passivationlayer 180 disposed on the data line 171 and the pixel electrode 191 andthe branch electrode 271 including the branch electrode 271 and thehorizontal/first connection part 272 of the branch electrode 271 anddisposed on the passivation layer 180 with a second interval from thedata line 171.

In an exemplary embodiment, the first interval between the pixelelectrode 191 and the data line 171 is greater than the second intervalbetween the reference electrode 270 and the data line 171.

In an exemplary embodiment, the liquid crystal display device includesthe reference electrode 270 disposed on the passivation layer 180 andincluding the branch electrode 271 and the connection part 272 connectedto the branch electrode 271 is disposed on the passivation layer 180such that a portion of the connection part 272 overlaps the firstinterval between the pixel electrode 191 and the data line 171.

In an exemplary embodiment, the overlapped portion of the first intervalbetween the pixel electrode 191 and the data line 171 and the connectionpart 272 is disposed adjacent to the data line 171 where the image isnot displayed.

Accordingly, the parasitic capacitances between the data line 171 andthe reference electrode 270 or the parasitic capacitances between thedata line 171 and the pixel electrode 191 is substantially reduced whilethe aperture ratio of the liquid crystal display device is significantlyincreased.

Another exemplary embodiment of a liquid crystal display device will nowbe described in further detail with reference to FIGS. 12 and 13. FIG.12 is a plan view of an exemplary embodiment of a liquid crystal displaydevice according to the present invention, and FIG. 13 is a partialcross-sectional view taken along line XIII-XIII of FIG. 12.

The exemplary embodiment of the liquid crystal display device shown inFIGS. 12 and 13 is substantially the same as the exemplary embodimentsof the liquid crystal display device shown in FIGS. 8 through 10 exceptfor a shielding electrode 88. The same or like elements shown in FIGS.12 and 13 have been labeled with the same reference characters as usedabove to describe the exemplary embodiments of the liquid crystaldisplay device shown in FIGS. 8 through 10, and any repetitive detaileddescription thereof will hereinafter be omitted or simplified.

In an exemplary embodiment, the liquid crystal display device furtherincludes the shielding electrode 88 disposed under the data line 171, asshown in FIGS. 12 and 13. The shielding electrode 88 may be disposed ina same layer including the gate conductor, and may be electricallyfloated. In an exemplary embodiment, the width of the shieldingelectrode 88 may be greater than the width of the data line 171 or thesemiconductor stripe 151.

The shielding electrode 88 effectively prevents light from entering thesemiconductor stripe 151 disposed under the data line 171, and undesiredactivation of the semiconductor stripe 151 by the light is therebyeffectively prevented.

Another exemplary embodiment will now be described in further detailwith reference to FIG. 14, which is a plan view of yet another exemplaryembodiment a liquid crystal display according to the present invention.

The structure of the liquid crystal display device of FIG. 14 issubstantially the same as the structure the liquid crystal displaydevice in FIGS. 8 through 10 except for the reference voltage line 131.The same or like elements shown in FIG. 14 have been labeled with thesame reference characters as used above to describe the exemplaryembodiments of the liquid crystal display device shown in FIGS. 8through 10, and any repetitive detailed description thereof willhereinafter be omitted or simplified.

As shown in FIG. 14, the reference voltage line 131 is disposed at themiddle of the pixel area of the liquid crystal display device. In anexemplary embodiment, the expanded portion 135 of the reference voltageline 131 is disposed at the center of the pixel area and the expandedportion of the reference electrode is disposed at the center of thepixel area.

In an exemplary embodiment, since the pixel electrode 191 of the pixeldoes not overlap the expanded portion 135 of the reference voltage line131, the contact hole 183 and the expanded portion 275 of the referenceelectrode 270, an edge of the pixel electrode 191 adjacent to the dataline 171 may have a cutout that surrounds at least a portion of thecontact area of the reference voltage line 131 and the referenceelectrode 270. Accordingly, the pixel electrode 191 disposed between thereference voltage line 131 and the reference electrode 270 is notoverlapping the contact area of the reference voltage line 131 and thereference electrode 270, and a short between the reference electrode 270and the pixel electrode 191 is thereby effectively prevented.

Another exemplary embodiment will now be described in further detailwith reference to FIG. 15, which is a plan view of another exemplaryembodiment of a liquid crystal display device according to the presentinvention.

The liquid crystal display device of FIG. 15 is substantially the sameas the liquid crystal display device in FIGS. 8 through 10 except forthe reference voltage line 131. The same or like elements shown in FIG.14 have been labeled with the same reference characters as used above todescribe the exemplary embodiments of the liquid crystal display deviceshown in FIGS. 8 through 10, and any repetitive detailed descriptionthereof will hereinafter be omitted or simplified.

As shown in FIG. 15, the gate line 121, which includes the gateelectrode 124, and the reference voltage line 131 are disposed on theinsulating substrate 110, the gate insulating layer 140 is disposed onthe gate line 121 and the reference voltage line 131 and thesemiconductor island 154, the ohmic contacts 163 and 165 are disposed onthe gate insulating layer 140, and the data line 171 and the drainelectrode 175, which include the source electrode 173, are disposed onthe gate insulating layer 140 and the ohmic contacts 163 and 165. Thepixel electrode 191 is disposed on the gate insulating layer 140 and aportion of the drain electrode 175 and the passivation layer 180 havingthe contact hole 183 is disposed on the pixel electrode 191, the dataline 171, the drain electrode 175 and the exposed semiconductor island154. The reference electrode 270 including the branch electrode 271 isdisposed on the passivation layer 180, overlapping the pixel electrode191.

Referring again to FIGS. 8 through 10, in an exemplary embodiment, thedata line 171 may include a first curved part having the chevron-likeshape and may be disposed at an intermediate area of the pixel area toobtain maximum transmittance of the liquid crystal display device. Theintermediate area of the pixel area may further include a second curvedpart that extends from the first curved part forming a predeterminedangle with the first curved part. The first curved part of the data line171 may form an angle in a range of about 5° through about 10°, e.g.,about 7°, with a rubbing direction of an alignment layer. The secondcurved part may be disposed adjacent to the intermediate area of thepixel area forming an angle in a range of about 7° through about 15°with the first curved part.

Further, the branch electrode 271 of the reference electrode 270includes a first part 271 a (shown in portion A) substantially parallelto the first curved part of the data line 171 and a second part 271 b(shown in portion A′) substantially parallel to the second curved partof the data line 171. The first part 271 a may form an angle of about 7°with the rubbing direction of the alignment layer and the second part271 b may form an angle in a range of about 7° through about 15° withthe first part 271 a.

Another exemplary embodiment will now be described in further detailwith reference to FIGS. 16 and 17. FIG. 16 is a plan view of stillanother exemplary embodiment of a liquid crystal display deviceaccording to the present invention, and FIG. 17 is a partialcross-sectional view taken along line XVII-XVII of FIG. 16.

The liquid crystal display device shown in FIGS. 16 and 17 issubstantially the same as the liquid crystal display device in FIGS. 1,2A and 2B except for the passivation layer 180. The same or likeelements shown in FIGS. 16 and 17 have been labeled with the samereference characters as used above to describe the exemplary embodimentsof the liquid crystal display device shown in FIGS. 1, 2A and 2B, andany repetitive detailed description thereof will hereinafter be omittedor simplified.

As shown in FIGS. 16 and 17, the gate line 121, which includes the gateelectrode 124, and the reference voltage line 131 are disposed on theinsulating substrate 110, the gate insulating layer 140 is disposed onthe gate line 121 and the reference voltage line 131, the semiconductorisland 154 and the ohmic contacts 163 and 165 are disposed on the gateinsulating layer 140, and the data line 171 and the drain electrode 175,which include the source electrode 173, are disposed on the gateinsulating layer 140 and the ohmic contacts 163 and 165. The pixelelectrode 191 is disposed on the gate insulating layer 140 and a portionof the drain electrode 175. The thickness of the pixel electrode 191 maybe in a range of about 400 Å through about 500 Å. The passivation layer180 having the contact hole 183 is disposed on the pixel electrode 191,the data line 171, the drain electrode 175 and the exposed semiconductorisland 154. The reference electrode 270 including the branch electrode271 is disposed on the passivation layer 180, overlapping the pixelelectrode 191.

As shown in FIG. 17, the liquid crystal display device includes thepassivation layer 180 having a dual-layer structure including a firstpassivation layer 180 p and a second passivation layer 180 q.

The first passivation layer 180 p and the second passivation layer 180 qmay have different refractive indexes. Specifically, the refractiveindex of the first passivation layer 180 p may be in a range of about1.4 through about 1.6, and the refractive index of the secondpassivation layer 180 q may be in a range of about 1.6 through about2.2. The first passivation layer 180 p and the second passivation layer180 q may be made of inorganic insulator, e.g., SiNx or SiOx. In anexemplary embodiment, the first passivation layer 180 p and the secondpassivation layer 180 q may be made of a same inorganic material, or maybe made of a different inorganic material. In an exemplary embodiment,the thickness of the passivation layer 180 may be in a range of about5500 Å through about 6500 Å, while the thickness of the firstpassivation layer 180 p and the second passivation layer 180 q of thepassivation layer 180 may be in a range of about 2800 Å through about3200 Å.

The refractive index of the first passivation layer 180 p and the secondpassivation layer 180 q are controlled by adjusting a pressure and flowrate of nitrogen (N₂) gas used in an exemplary embodiment of a chemicalvapor deposition (“CVD”) process, which is a process of depositing thefirst passivation layer 180 p and the second passivation layer 180 q.

FIG. 18 includes graphs of refractive index versus flow rate of N₂ gas,in standard cubic centimeter per minute (sccm), and of refractive indexversus pressure of N₂ gas, in Pascal (Pa), used in an exemplaryembodiment of a chemical vapor deposition process according to thepresent invention. As shown in FIG. 18, the refractive index of thefirst passivation layer 180 p or the second passivation layer 180 q isdetermined by adjusting the pressure and flow rate of the N₂ gas. In anexemplary embodiment, the first passivation layer 180 p and the secondpassivation layer 1801 of the liquid crystal display device havedifferent nitrogen contents, and, more particularly, the nitrogencontent of the first passivation layer 180 p may be greater than thenitrogen content of the second passivation layer 180 q.

As described above, by controlling the nitrogen content of both thefirst passivation layer 180 p and the second passivation layer 180 q,the refractive indexes of the first passivation layer 180 p and thesecond passivation layer 180 q may be predetermined, and transmittancedeterioration, due to a haze phenomenon from crystallization of thepixel electrode 191 or reference electrode 270 made of a transparentmaterial, is thereby reduced and/or is effectively prevented in anexemplary embodiment of a manufacturing process of the liquid crystaldisplay device according to the present invention, as will now bedescribed in further detail with reference to FIGS. 19 and 20.

FIG. 19 is a graph of percent transmittance (% T) of an exemplaryembodiment of a liquid crystal display device versus thickness of apassivation layer 180 thereof, in angstroms (A), and FIG. 20 is a graphof transmittance of the liquid crystal display device corresponding torefractive indexes of the first passivation layer 180 p and the secondpassivation layer 180 q.

As shown in FIG. 19, as the thickness of the passivation layer 180changes, the transmittance of liquid crystal display device changes.When the thickness of the passivation layer 180 is in a range of about2800 Å through about 3200 Å or in a range of about 5500 Å through about6500 Å, the transmittance of the liquid crystal display device issubstantially improved relative to other thickness ranges. Accordingly,the transmittance of the liquid crystal display device is substantiallyimproved when the thickness of the passivation layer 180 is in a rangeof about 5500 Å through about 6500 Å.

Referring to FIG. 20, the transmittance of the liquid crystal displaydevice also changes in accordance with the refractive indexes of thefirst passivation layer 180 p and the second passivation layer 180 q ofthe passivation layer 180. The transmittance of the liquid crystaldisplay device is about 0.820 through about 0.840 when the passivationlayer 180 is formed to have a single layer. As shown in FIG. 20,however, in an exemplary embodiment in which the passivation layer 180is formed in a dual-layer structure including the first passivationlayer 180 p having refractive index in a range of about 1.4 throughabout 1.6 and the second passivation layer 180 q having refractive indexin a range of about 1.6 through about 2.2, the transmittance of theliquid crystal display device is substantially increased to a range ofabout 0.900 through about 0.920.

Changes in transmittance of a liquid crystal display device now will nowbe described in further detail with reference to an experimentalexample. In the experimental example, the haze phenomenon was measuredwhen the passivation layer 180 is formed in a single layer (Case A) andwhen the passivation layer 180 has a dual-layer structure including thefirst passivation layer 180 p and the second passivation layer 180 qhaving different refractive index (Case B).

The following Table 2 shows the condition of chemical vapor depositionprocess of the first passivation layer and the second passivation layerused in the experimental example and the result of haze phenomenon.

TABLE 2 First passivation layer Second passivation layer Haze RefractiveRefractive phenom- Thickness index Thickness index enon Case A 6000 Å1.9 — — High Case B 2800 Å- 1.4-1.6 2800Å- 1.6-2.2 Low 3200 Å 3200Å

FIGS. 21A and 21B are microphotographs showing cross sections of atransparent electrode, which includes indium (In), when the passivationlayer 180 is formed as a single layer and when the passivation layer 180has a dual-layer structure including the first passivation layer 180 pand the second passivation layer 180 q having different refractiveindexes, according to an exemplary embodiment of the present invention.

Referring to FIGS. 21A and 21B and Table 2, as compared to thepassivation layer 180 formed in a single layer, the haze phenomenon issubstantially improved, e.g., is effectively prevented, in an exemplaryembodiment in which the passivation layer 180 has the dual-layerstructure including the first passivation layer 180 p and the secondpassivation layer 180 q having different refractive index. Accordingly,in an exemplary embodiment, the reduction of transmittance of the pixelelectrode 191 and the reference electrode 270 by the haze phenomenon issubstantially reduced and/or is effectively prevented.

Another exemplary embodiment of a liquid crystal display device will nowbe described in further detail with reference to FIGS. 22 and 23. FIG.22 is a plan view of another exemplary embodiment of a liquid crystaldisplay device according to the present invention, and FIG. 23 is apartial cross-sectional view taken along line XXIII-XXIII of FIG. 22.

The liquid crystal display device of FIGS. 22 and 23 is substantiallythe same as the liquid crystal display device in FIGS. 8 through 10except for the passivation layer 180. The same or like elements shown inFIGS. 22 and 23 have been labeled with the same reference characters asused above to describe the exemplary embodiments of the liquid crystaldisplay device shown in FIGS. 8 through 10, and any repetitive detaileddescription thereof will hereinafter be omitted or simplified.

As shown in FIGS. 22 and 23, the gate line 121, which includes the gateelectrode 124, and the reference voltage line 131 are disposed on theinsulating substrate 110 and the gate insulating layer 140 is disposedon the gate line 121 and the reference voltage line 131. Thesemiconductor island 154, the ohmic contacts 163 and 165 are disposed onthe gate insulating layer 140, and the data line 171 and the drainelectrode 175, which include the source electrode 173, are disposed onthe gate insulating layer 140 and the ohmic contacts 163 and 165. Thepixel electrode 191 is disposed on the gate insulating layer 140 and aportion of the drain electrode 175, and the passivation layer 180 havingthe contact hole 183 is disposed on the pixel electrode 191, the dataline 171, the drain electrode 175 and the exposed semiconductor island154. The reference electrode 270 including the branch electrode 271 isdisposed on the passivation layer 180, overlapping the pixel electrode191.

As shown in FIG. 23, the liquid crystal display device includes thepassivation layer 180 having a dual-layer structure including the firstpassivation layer 180 p and the second passivation layer 180 q.

The first passivation layer 180 p and the second passivation layer 180 qmay have different refractive indexes. Specifically, for example, therefractive index of the first passivation layer 180 p may be in a rangeof about 1.4 through about 1.6, and the refractive index of the secondpassivation layer 180 q may be in a range of about 1.6 through about2.2. The first passivation layer 180 p and the second passivation layer180 q may be made of inorganic insulator, e.g., SiNx or SiOx. In anexemplary embodiment, the first passivation layer 180 p and the secondpassivation layer 180 q may be made of a same inorganic material. Inanother exemplary embodiment the first passivation layer 180 p and thesecond passivation layer 180 q may be made of different inorganicmaterials. In an exemplary embodiment, the total thickness of thepassivation layer 180 may be in a range of about 5500 Å to about 6500 Å,while the thickness of the first passivation layer 180 p and the secondpassivation layer 180 q of the passivation layer 180 may be in a rangeof about 2800 Å to about 3200 Å.

As described above, the refractive index of the first passivation layer180 p and the second passivation layer 180 q may be predetermined duringa process of depositing the first passivation layer 180 p and the secondpassivation layer 180 q by adjusting the pressure and flow rate of N₂gas that is used in the CVD process according to an exemplaryembodiment.

As also described above, the transmittance deterioration, e.g., the hazephenomenon due to crystallization of the pixel electrode 191 and/or thereference electrode 270 made of a transparent material in themanufacturing process of the liquid crystal display device, iseffectively prevented by forming the passivation layer 180 in adual-layer structure including the first passivation layer 180 p and thesecond passivation layer 180 q having different refractive index.

The present invention should not be construed as being limited to theexemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this disclosure will be thorough andcomplete and will fully convey the concept of the present invention tothose skilled in the art.

In additional exemplary embodiments, for example, the referenceelectrode may have a surface shape without a specific pattern in thepixel area and the pixel electrode may include a plurality of linearbranch electrodes and a branch electrode connection part connectingthem. Further, the present invention can be applied to not only when thecolor filter and light blocking film are formed on the upper plate, butwhen the color filter and light blocking film are formed on theinsulating substrate, as well.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit or scopeof the present invention as defined by the following claims.

What is claimed is:
 1. A liquid crystal display device comprising: afirst substrate; a second substrate facing the first substrate; a liquidcrystal layer interposed between the first substrate and the secondsubstrate; a gate line disposed on the first substrate; a data linedisposed on the first substrate; a pixel connected to the gate line andthe data line, the pixel comprising: a thin film transistor including asource electrode, a drain electrode, and a channel area, disposed on thefirst substrate, and connected to a first portion of the data line; apixel electrode connected to the thin film transistor and including anopening formed therein overlapping the thin film transistor; and areference electrode disposed on the first substrate and overlapping thepixel electrode, wherein a first opening is formed in the referenceelectrode overlapping the channel area between the source electrode andthe drain electrode.
 2. The liquid crystal display device of claim 1,wherein the source electrode is a portion of the data line, the drainelectrode parallels the data line, and the channel area is disposedunder the data line and the drain electrode.
 3. The liquid crystaldisplay device of claim 1, wherein the reference electrode comprising: afirst connection part disposed substantially parallel to the data line;a second connection part disposed substantially parallel to the gateline and connected to the first connection part; and a branch electrode.4. The liquid crystal display device of claim 3, wherein the branchelectrode comprises a first part; a second part connected to the firstpart; and a third part connected to the first part and the secondconnection part, wherein the second part forms a first angle with thefirst part, the third part forms a second angle with the first part anda third angle with the second connection part.
 5. The liquid crystaldisplay device of claim 4, wherein the first connection part overlaps asecond portion of the data line.
 6. The liquid crystal display device ofclaim 5, wherein a second opening is formed in the first connection partof the reference electrode and overlaps a second portion of the dataline.
 7. The liquid crystal display device of claim 1, wherein the pixelfurther comprises a shielding electrode disposed under the data line andon the first substrate and overlapping a second portion of the dataline.
 8. The liquid crystal display of claim 1, further comprising areference voltage line disposed on the first substrate, and wherein thereference voltage line is disposed adjacent to the gate line andincludes an expanded portion connected to at least one of a red pixeland a blue pixel.
 9. The liquid display device of claim 1, furthercomprising a reference voltage line disposed on the first substrate; anda plurality of gate lines disposed on the first substrate, and whereinthe reference voltage line is disposed between two adjacent gate linesof the plurality of gate lines and includes an expanded portionconnected to a green pixel.
 10. The liquid display device of claim 9,wherein the pixel electrode of the pixel does not overlap the expandedportion of the reference voltage line.
 11. The liquid display device ofclaim 1, further comprising a dual passivation layer disposed betweenthe reference electrode and the pixel electrode, the dual passivationlayer comprising: a first passivation layer; and a second passivationlayer, wherein a refractive index of the first passivation layer isdifferent from a refractive index of the second passivation layer. 12.The liquid crystal display device of claim 11, wherein the nitrogencontent of the first passivation layer is greater than the nitrogencontent of the second passivation layer.